Projector



July22,1941. 'l E ,BANCMWT 2,250,174

PROJECTOR -Fi1edAug. 16, 1939 Ja'm es E. Baz: craft.

ATT EYS.

Puieuied Julyv z2, 1941 n VPROJECTOR James E. Bancroft, Jamaica; N. Y., assigner to American Bowlingl and Billiard Corporation, New York, N. Y., a corporation ot New York Application August 1s, i939, serial No. 290,426

(c1. sai-24) 4 Claims.

My invention relates generally to projectors and more particularly to an arrangement in a projector for presenting to an observer an uni changed image of an object.

As my invention serves eiectively for project.

ing scores in games such as bowling, I have illustrated in the drawing the'embodiment of my invention in a projector for that purpose, and

will describe my invention in connection with` such an embodiment. It will be understood,how

ever, that this is done only by way 'of exemplifi-` cation as one of the practical applications of my invention and that my invention is not to be limited by such exempliilcations, except to the extent called for by the language of the claims.

In the conventional bowling alley a scorer sits at the approach end` of the alley facing in the direction of the pin end and records the scores on a pad that is right in front of him. Players and on-lookers keep themselves informed of the progress of the game by looking at this `score pad, but when a crowd is lodged'around `the score pad, this becomes 'rather difilcult because of the mulling around the score keeper.

One of the objects of mylinvention is an arrangementwhereby the score keeper who writes the score, as well as the onlookers who want to look at what is written aswell as to see the play, can have presented, in their line of vision as they view the play, on the score pad, an unchanged image on a larger scale. This general object I attain by an arrangement whereby inversions laterally and vertically are compensated for and balanced out, so that there is presented, in the line of vision of any observer, an uninverted and unreversed image, so that the observers can get a true picture of the score sheet as it is being recorded, and so that the score keeper, who makes the recordations, can check the accuracy of the recordations merely by watching the image of the recordation. l Y

In the illustrated embodiment, I show the attainment of these objectives by employing in the optical system at least two mirrors symmetrically positioned in reference to theprojected rays, and each of .which will give aconventional reflection and which jointly give the result that each balances out of the other the reversal which a conventional mirror gives. f

In accordance with the accomplishment of my" general objectives by this arrangement, I have furthenthat the line along which theymeet be symmetrically positioned with reference to the image forming rays.

These objects and such other objects as will hereinafterappear or be pointed out are attained in the illustrative embodiments of my invention shown in the drawing, in which:

Figure 1 is a -view in perspective showing my projector in use on a bowling alley;l

Figure 2 is a transverse sectional view through lmy improved projector taken substantiallyon the Aline 2-2 of Figure 3, lookingin the direction of the arrows;

Figure 3 is a sectional view taken substantially on the line 3-3 of Figure 2 looking in the direction'of the arrows; Y Y

Figure 4 is a sectional view of my improved reiiector taken substantially on the line 4 4 of Figure 3, looking in the direction of the arrows;

Figure 5 is aiace view of the reflector of Il lg-A ure 4;

Figures 6 and 7 are respectively sectional and face views, similar toFigures 4 and 5, of a modied form of reflector; y

Figure 8 is a Vview in perspective of the score keeping table, within which is held the master score sheet that constitutes the object an image of which is projected by my invention; and

Figures 9 and 10 are diagrammaticl views showing the optical principles of my invention, the former illustrative of the projection of horizontal linear object elements parallel to the projection.

screen, and the latter illustrative of the projection of horizontal linear object elements perpendicular to the screen.

In Figure 1 I have shown the application of my improved projector to. a bowling alley. In this figure A designates the bowling alleys, B is thek foul line and C is the pit end of the alleys, where the pins are set up. D is the space Within which the players stand, while E designates seats provided for players. At F is shown a screen suitably supported, as by being hung from the ceiling, so that it does not obstruct the scorers and the spectators clear view of the bowling alley', and so that its surface is in full view of spectators looking down the 'alley to watch the play. At G I have shown my improved projector so positioned that the: scorer H may take his position in front of it and look down the alley and observe what transpires in the alley. As the scorer observes lthe play he notes down the score on the ltable of the .projector G,' theconstruction of whichwill be more fully described hereinafter,I and as he does so the projector throwsfthe image of the score1 noted down by the scorer orlthe` screen F, so that the score is visible to the spectators. ,n

While I have illustrated by way of example, one particular position of my projector in relation to the alleys, it is toV be understood that for particular purposes, other positions may be found more suitable.

In Figures 3 and 2, I have shown the arrangement of the parts of the projector G, and itl will be observed that it comprises a lowercasing or table 20, the upper end of which has in it a'transparent or translucent plate 2|.- Inside the cas ing-is shown a source of light such as the ncandescent bulb 22; any bulb) suitable for projection work, such as a bulb of the stereoptico or other concentrated filament type is to be preferred. The light from this bulb isy thrown on the plate 2| by a condenser system 23 which may be adjustably mounted (not shown) for obvious reasons.

Twoarms 24 and 25 are mounted on the casi-ng" 29 so as to extend upwardly therefrom and carry at their upper ends the projector system proper which is shown as comprising a casing 26 which may -be mounted for pivotal movement (not` shown) on the arms 24 and 25 so that the direction of the projected rays may be varied.

Within the vcasing 26 is mounted a projector lens system 21 which may be slidable in the casing 26 soA that it may be properly focused, and

" this lens system 21 is adapted to receive rays from an object situated on the table 2| and to peculiar construction, from which the rays pass to a .plane reflector 29 which throws them through a window 39 in the casing on the vpro- Referring now to Figure 8, I have there shown Ain perspective the top 31 lof the casing 20, and

the plate or window 2| therein. The object which is to be projected is placed on the plate 2|, and in accordance with the general principles of this type of projection, it must as a whole be transparent or translucent, so that light rays from the object may be pickedup by the lens system 21 and transmitted to the screen.

While this desired result may be effected in various ways, I may mention two that I have found particularly effective in practice. Accord,-

ing to one way thescore card frame may be im` printed in some manner on a transparent sheet,

Vsuch as a sheet of Celluloid or Cellophane, and

the score recorded thereon by the scorer in some suitable manner, such as by ink or crayon. For projection purposes the score sheet is laid on the table 2 l and after having served its purpose it may be removed and discarded, or, on the other hand, it may be filed away to serve as a permanent record. Obviously the surface of the transparent sheet may be matted, so as to render the sheet.

translucent instead of transparent. By imprinting the score :frame in some permanent fashion and using ink, crayon or the like that may be erased, obviously the same score sheet may be direct them rst toward a reflector unit 28, of

The reflector unit 28 maybe pivotally mounted, y

as shown, for purposes of adjustment, as will be obvious.

The construction of the' reflector unit 28 is illustrated in detail in Figures 4 and 5. On referrlng to these figures it will be observed that it is shown as comprising two reflecting surfaces 3| and 32 .positioned at substantially a right angle to each other and that the optical axis 33 of the projecting lens system'21 intersects their meeting edge 34. When inuse in my projector thelv surfaces 3| and '32 are positioned symmetrically relatively to the axis 33, that is, the said axis lies in a plane that bisects the right angle between the surfaces 3| and 32 whereby said axis lies in a plane that forms an angle of with each of said surfaces 31 and 32. y

It will be understood that where I refer to optical axis of the lens system that I do not thereby intend to limit myself to an axis that is necessarily rectilinear, but that I also include in said term an axis portions of which are redirected, as byreflectionv or by refraction, such as the axis shown in Figure 10 in which the broken 1ine,ee1e2-e3. is the opticalaxis of the lens system. f

The reflecting surfaces 3| and 32 are suitably 'supported by mounting them on a frame such as shown at 35' and they may be conveniently, although not necessarily, formed of two separate pieces held` together by said supporting means 35, as indicated in Figure 4. v 4

An alternative form of reflector unit, designated by the numeral 28', is shown in Figures 6 the and V'1. It comprises a pair of planereflectorsv 3|' and 32' disposed in'spaced lrelation in planes at right angles to each other and suitably held in this position as by a frame 36.

used repeatedly, since by erasing the score marks, it will be available for a freshi score record. It is also within my contemplation to make the plate 2|, itself serve as a score card. In that case the score frame will be formed in some suitable or preferred manner directly on the plate 2| and the score is entered directly thereon in some medium that may be removed, sd as to enable repeated use of the sameplate. If desired, of course, an `individualplate may be used for each score andthe plates with their scores mayA be preserved. The plate 2| may obviously either be transparent or translucent.

For the optical principles underlying my invention I will-now refer to Figures 9 and 10.-

Figure 9 illustrates diagrammatically the projection, on the screen F, of an arrow. a-c-b vpositioned so as to lie transversely on the top 31- of the casing or table 29, its projection or image` on said screen being designated by the letters a4-c'1-b4. The scorer is supposed to be sitting in front of the score table, as inFigure 1, so that he an look at the bowling alleys to watch the play and make entries of the score, and, he will at the same time face the screen, as do also the spectators. The head a and the tail b of the arrow af-c-b will be assumed to be'equidistant from his eyes.

The diagram of Figure 9 is disposed in a plane. It is to be understood however that its lower portion is in reality at right angles to its upper portion, which change in angle is effected by the angular tilt of the reflectors 28 and 29, as shown in Figure 3, and diagrammatically in Figure 10.' However the explanation of this phase of the optical principles is most conveniently and simpome cf, ih other words it fouo'ws theorem sus, um a um une c A ray proceeding from thearrowhead a' and passing through the optical ofthe lens system 31, will strike the l'llht portion of the reflector 2l ata point al, from which itwill be reflected to a point a on theleft portion of the reector 2l, after which it will be i'ellected to a point aa on the reflector 20, from which it reaches the point a* on the screen F. It will-be 'observed l that the point a ofthe object and the correwnne' :have

embodiment of-myinvetion and one modifica-l tion thereof. it will be understood that the same maybeembcdiedinmanyotherforms andmodif `lied inmany other ways without departing fromvthe spirit thereof. as will be' obviousto those .skilled in the art, andthat the disclosure here'- in is by way of illustration merely, and is not sponding point a4 ofthe screen' image both lie a on the same side of the optical axis. The inis featured diagrammatically. For simplicity of positioned, so that the optical axis of the lens system 21 pierces iii` at its mid-point e, such axial ray will strike reilector .2l at a point-e1, proceed reector 29, w ch it strikes `at e. and will reach the screen F, which it strikes-at the image point e3. 4 i

yla ray from the arrow tail, d, passing through version due to thev lens system 21 has been cor- 1 to be 'interpreted in a limiting sense, and tliat I do not limit myself other lthan as called vfor by the. prior art. l

Having thus'described my invention 'and il lustrated its use, what I claim as new and desire to secure by Letters Patent, is:

l.. In combination in aninstallation for bowling alleys and the like, a vertical screen,and a projector comprising a casing, theupper end of f saidcasingbeinglighttransmittingandhaving a substantially fiat upper surface, a source of Y light in said casing. a condenser system adapted to collect light rays from said source and to illuminate the said upper surface of said casing, a second casing positioned abovesaid mst casing, a projecting lens system in saidfsecond casing v adapted to receive rays from said illuminated upper surface of said first casing, 'reiiectlnsmeans adapted to invert rays in relativ to one the optical center of the lens system 21, will. f

f/strike successively the reector 28 at point d1, the reflector, at ,d2 and the screen F at the point d3. Similarly a ray passing through the opticalcenter of lens system 21 from the head1 of the arrow, wm take the path f1, f2, f.

It will be observedl that the point'a of the ob- 4ject, which is the point farthest removed from the scorer, becomes the highest point a? of the screen image. I

It will now be clear that the projection has produced a true image, without inversion, in a vertical plane, of an object lying in a horizontal plane. Manifestly by adjustment of the reector unit 28 and the mirrorX29 the plane, of` the lobject may be `varied from the horizontal, without departing from the principles explained and similarly the plane of the screen F may be varied from the vertical.

Manifestly, also, the same results may be secured where the elements 21, 28 and 29 are ar ranged in an optical sequence different from the one shown illustratively in the drawing. f

The modified form of reflector 28' shownin Figures 6 and 7 is found to/function in substan-V tially the same way as the reflector 28 of Figures 4 and 5. It is found, however, that the space between the sections 3i' and 32 causes a loss of light in the elements of the image parallel to the vertical plane containing the optical axis of the lens, that is the line e, el, e3, e3 and adjacent to said plane. If said space is made suiliciently great a gap is produced in the middle of the ,image and only the lateralhalves of the image appear at both-sides of said gap. -It is therefore obvious that the said spacing must be regulated so as to avoid this gap.

transverse axis only, saidv means comp n g a pair of plane reflecting surfaces disposed substantially at a-right angle to each other, .and disposed symmetrically in relation to the optical axis of the lens, and means for transmitting said rays lfrom said reflecting means to said screenV without further inversion. A 2; In combination in an installation for bowling alleys and the like.' a vertical screen, and a projector comprising a casing, the upper end of said casing being light transmitting and having a substantially fiat upper surface, a source of light in said casing, a condenser system adapted to collect light rays from said source and to illuminate the said upper surface of said casing,`

a second casing positioned above said first casing, a projecting lens system in said second casing adapted to' receive rays from said illuminated upper surface of said first casing, reflecting means adapted to invert raysin relation to one transverse axis only, said means comprising a pair of plane reflecting surfaces disposed substantially at a. rightl angleto each other, and also disposed symmetricallygin relation to the optical axis of the lens, and a single plane reflector' adapted to receive the raysi'rom said reflecting' means and to direct them to said screen.

3. In aprojector, in combination, a lens system, and means for inverting the image produced by said lens system relatively to a transverse axis, said means comprising a pair of' plane light re-A flecting surfaces disposed substantially at a right angle to each other, with the axis of the lens system positioned in la plane bisecting the solid' angle between said surfaces, and said surfaces being spaced from each other symmetrically rela'- tively to said plane. y

4. In combination in an installation for bowling alleys and the like, a screen, and a. projector comprising a casing, the upper end of said casing being light transmitting and having a substantially iiat upper surface, whereby a score keeper may position a. translucent score card thereonon which he may enter the score while it is positioned on said upper surface, a source of light in said casing, a condenser system adapted to collect light rays from said source and to illuminate the said upper surface of sai dcas'ing,

s. second casing positioned above said first casing,

and disposed symmetrically in relation to the optical axis of the lens system, and a plane re ector in said second casing positioned in the optical axis of the lens system, said lens system, said reflecting unit and said plane reflector cony stituting an optical system for transmitting an image of the score card to the screen.

. JAMES E. BANCROFT. 

